3.In a television interview shortly after Mr Mitchell touched down, Israel's prime minister said there would be no freeze in the construction of new Jewish homes in East Jerusalem.

touch down降落, 着陆

例句：We should touch down very soon now.

我们很快就要着陆了。

4.The BBC correspondent says the energy crisis has contributed to political instability.

contribute to促成

例句：Smoking is a major factor contribute to cancer.

吸烟是致癌的一个重要因素。

1.Our system only works, our markets are only free when there are basic safeguards that prevent abuse, that check excesses, that ensure that it is more profitable to play by the rules than to game the system.

参考翻译：

只有在存在基本的保障措施，能够防止滥用，防止过量，能够确保执行这些规则能够比下赌注更加有利的情况下，我们的体系才能正常运转，我们的市场才是自由市场。

结构分析：

Our system only works, our markets are only free是主句，后面when引导的是表明前面这样的结果实现所需的条件，there are basic safeguards，后面三个that引导的是定语从句，修饰的都是safeguards。that it is more profitable是宾语从句，是ensure的宾语。more...than，进行对比的两者是：play by the rules和game the system。

2. His lawyer Howard Jacobs said the positive test had been caused by Mr Merritt's use of an over-the-counter male enhancement drug which contained the banned steroid DHEA.